While some people get too wrapped up in monitoring web analytics data such as toolbar PageRank, top 30 rankings and number of daily visitors, there are some crucial metrics to follow and act on in order to improve your website and your search engine rankings.

To get a real sense for how your website is performing, spend your time monitoring things that illustrate successes and failure, such as conversion rates, how many backlinks you've collected and how engaged you visitors are. Here's a look at the three online marketing metrics you'll want to pay close attention to:

1. Conversion rate and goal completion
If you're investing time and money in building a site and expanding your web presence, be sure you're getting something of value in return. Whether your goal is increasing online sales or simply educating website readers about a certain topic, have a method for tracking conversion rates -- the ratio of website visitors who convert from visits into desired actions, such as signing up for a newsletter or making a purchase.

In general, your best tool will be the free Google Analytics, which can track everything from website sales to whitepaper downloads. Another option is an analytics service such as KISSmetrics, which can track metrics across e-commerce, mobile apps, social games and more. Prices start at $29 per month.

2. Backlink profile
Following Google's recent Penguin algorithm update, it's clearer than ever that the quality of the links pointing at your website matters in terms of search engine optimization (SEO). If you don't know what types of links are in your backlink profile, you risk being penalized by the search engines without ever trying to remedy the situation.

To gain a better understanding of the composition of your backlink profile, consider using a service such as Majestic SEO (plans start at $49. 99/month) or the Open Site Explorer ($99/month, following a free trial). Although you can get some information from Google's and Bing's Webmaster Tools programs, you won't get the full picture unless you pay for a third-party SEO tool.

Once you've accessed your backlink profile, here are a few things you'll want to look for:

Are there any "bad neighborhood" links pointing at your website? Bad neighborhood links include pornography, gambling and other questionable sites.

Do your backlinks use varied, natural sounding anchor text? If you've carried out optimized link-building campaigns in the past, your profile may include too high a percentage of keyword-based anchor texts. For example, using SEO keywords such as "Mexico best hotel deals" instead of "click here" for your link text. These patterns may indicate over-optimization to the search engines, which may result in future penalties.

Do your links come from sites that were built solely for SEO purposes? As the search engine algorithms become more complex, they're increasingly able to detect these websites, which often contain scraped or spun content, basic site designs and no detectable human presence. That can lead to penalties based on perceived manipulation.

If you detect any of these low-quality backlinks pointing at your website, do your best to remove them. Be sure to keep track of your efforts. Webmasters may refuse to respond to your requests to remove their links, but at least you'll have the supporting documentation needed to file a reconsideration request should a search engine penalize you. You can detect such penalties through a loss of traffic or a decrease in your site's natural search results rankings.

In addition, make tracking your backlink profile an ongoing effort. Check in at least once a month to try to prevent penalties before they occur.

3. Visitor engagement
This refers to how much time visitors spend on your site and how much value they see in your content. It can be tracked in a number of ways, including:

Average time on site, which should be as high as possible.

Bounce rate, which measures the number of visitors who don't navigate beyond the first page of your website that they land on. It should be lower than 50 percent.

Average pages per visit, which should also be as high as possible.

Number of social media shares, which should be high in order to demonstrate that visitors find enough value in your content to share it with friends.

Visitor engagement is important because of the potential business gains from providing customers with an engaging on-site experience. But many of the metrics described above also increasingly figure into search engine rankings, giving your site an SEO boost.

If your visitor engagement metrics aren't as strong as they should be, isolate and improve your site's weaker areas. It may seem like extra work, but the payoff in increased conversions and higher search engine rankings can be well worth it.